The Improvement in Measuring Position and Orientation of Laparoscopic Tools Using the Cross Correlation Method

A new ultrasound wireless positioning system is developed that gives the surgeon the exact 3D location and orientation of the instruments in the patient. The measuring system employs ultrasound markers/ transmitters placed on the instruments, outside of the human body. Knowing the dimensions of the usually rigid instruments it is possible to calculate their position and orientation inside the patient from the markers’ positions. The detection of the marker positions is realized by an array of ultrasound receivers. Using the cross-correlation method for the time of flight determination (transmitter–receiver) we obtained a resolution of 0.7 mm in determining the marker positions. A wireless radio wave system (RF) is used to trigger the ultrasound markers. Keywordsultrasound, 3D detection, laparoscopic instrument